How photosynthesis and respiration feed each other

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Use this

   Flow diagram drawn as a loop (model, not to scale), inside a leaf cell. Two process boxes: photosynthesis, in the chloroplast, on the left; cellular respiration, in the mitochondrion, on the right. An arrow from photosynthesis to cellular respiration carries: glucose; oxygen. The arrow from cellular respiration back to photosynthesis is blank. A wavy arrow points into photosynthesis: light energy. A wavy arrow points out of cellular respiration: energy moved to ATP and heat.

2. 1.

   Ari reads a loop diagram of a leaf cell. The arrow from cellular respiration back to photosynthesis is blank. Which substances belong on it?

   • Carbon dioxide and water
   • Glucose and oxygen
   • Nothing, since the processes share no substances
   • Light energy and heat

3. Use this

   Flow diagram drawn as a loop (model, not to scale), inside a leaf cell. Two process boxes: photosynthesis, in the chloroplast, on the left; cellular respiration, in the mitochondrion, on the right. An arrow from photosynthesis to cellular respiration carries: glucose; oxygen. An arrow from cellular respiration back to photosynthesis carries: carbon dioxide; water. A wavy arrow points into photosynthesis: light energy. A wavy arrow points out of cellular respiration: energy moved to ATP and heat.

4. 2.

   Bo reads that photosynthesis hands glucose and oxygen to cellular respiration. What does cellular respiration do with them?

   • Turns them into light energy for the leaf
   • Uses them as its starting substances
   • Makes them again from carbon dioxide and water
   • Ignores them and runs on its own supply
5. 3.

   Esme counts the arrows that carry matter between the two boxes. How many are there, and which way do they point?

   • Zero, since the boxes pass no substances
   • Two, both from respiration to photosynthesis
   • Two, one pointing each way
   • One, from photosynthesis to respiration
6. 4.

   Jun reads a leaf cell with two organelles, A and B. Which pair of names fits A and B?

   • A is the nucleus and B is the cell wall
   • A is a mitochondrion and B is a chloroplast
   • A is a chloroplast and B is a mitochondrion
   • A is a chloroplast, and the cell has no organelle B

7. Use this

   Flow diagram drawn as a loop (model, not to scale), inside a leaf cell. Two process boxes: photosynthesis, in the chloroplast, on the left; cellular respiration, in the mitochondrion, on the right. An arrow from photosynthesis to cellular respiration carries: glucose; oxygen. An arrow from cellular respiration back to photosynthesis carries: carbon dioxide; water. A wavy arrow points into photosynthesis: light energy. A wavy arrow points out of cellular respiration: energy moved to ATP and heat.

8. 5.

   Luz sees a chloroplast release oxygen in a leaf cell. Which part of the same leaf can use some of that oxygen?

   • The chloroplast, to make more glucose
   • The mitochondria, but they work after dark and pause by day
   • The leaf's own mitochondria, for respiration
   • No part, since plant cells take in no oxygen
9. 6.

   Milo reads a word list. Which meaning matches the term photoautotroph?

   • An organism that does photosynthesis but not respiration
   • An organism that gets energy from chemicals, not light
   • An organism that must take in sugars made by others
   • An organism that uses light to make its own food
10. 7.

    Noah reads a word list. Which meaning matches the term heterotroph?

    • An organism that runs on light and needs no sugar
    • An organism that makes its own sugar from light
    • An organism that relies on sugars made by others
    • An organism that has no link to photosynthesis
11. 8.

    Pia reads that, in the loop, oxygen from photosynthesis is called a byproduct. What does that word mean here?

    • A leftover that no cell can use
    • A substance one reaction releases that another can use
    • A substance made by animals, not by plants
    • A substance the cell absorbs straight from light

12. Use this

    Flow diagram drawn as a loop (model, not to scale), inside a leaf cell. Two process boxes: photosynthesis, in the chloroplast, on the left; cellular respiration, in the mitochondrion, on the right. An arrow from photosynthesis to cellular respiration carries: glucose; oxygen. An arrow from cellular respiration back to photosynthesis carries: carbon dioxide; water. A wavy arrow points into photosynthesis: light energy. A wavy arrow points out of cellular respiration. Its label is blank.

13. 9.

    Tala reads the wavy arrow that points out of cellular respiration. Its label is blank. What does it carry?

    • Energy released at night and paused by day
    • Energy moved to ATP, plus heat
    • Light energy sent back to photosynthesis
    • New energy created by the cell

14. Use this

    Flow diagram drawn as a loop (model, not to scale), inside a leaf cell. Two process boxes: photosynthesis, in the chloroplast, on the left; cellular respiration, in the mitochondrion, on the right. An arrow from photosynthesis to cellular respiration carries: glucose; oxygen. An arrow from cellular respiration back to photosynthesis carries: carbon dioxide; water. A wavy arrow points into photosynthesis: light energy. A wavy arrow points out of cellular respiration: energy moved to ATP and heat.

15. 10.

    Zee reads the whole loop. Which statement about energy in the loop is right?

    • Energy goes round and round like the matter does
    • Energy enters as heat and leaves as light
    • Energy is made fresh by the leaf cell
    • Energy enters as light and some leaves as heat